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Nobody knows about RR



 
 
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  #51  
Old July 29th 05, 12:17 AM
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Default Nobody knows about RR

Neil Brooks writes:

I thought that makers of bicycle tires would have experimentally or
scientifically based knowledge as a foundation of their
production.


I jumped in late and, unfortunately, haven't caught this thread in
its entirety, so forgive me if this has already been posted.


Interesting article:


Adobe document p.8
Magazine p.14


http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf

Along with its testing and conclusions, it makes reference to the
following sources (which I haven't attempted to locate) of RR test
data:


Cycling Plus, issue 62 (Feb. ?97) ?Winter tyres?; Cycling Plus, issue
68 (Mid-summer ?97) ?Road tyres?; Cycling Plus, issue 81 (Aug ?98)
?Time-trial tyres?; Total Bike, issue 6 (Oct ?97) ?MTB tyres?; and
BHPC Newsletter, issue 58, ?MTB tyres?.


The section on rolling resistance (pp 14) has a disconcerting flavor
to it in two ways. First the author attempts to establish credibility
through his years as an engineer and long association with recumbents.
Then the test method is explained showing that no direct measurements
of drag were used but rather the derivation of drag by differentiation
of rolling speed.

http://www.terrymorse.com/bike/imgs/rolres.gif

Printing a table of myriad numbers may be a good archive but such data
is better displayed in curves and preferably curves made of more than
one data point. What we have in the IHPVA report is none of that. In
fact the information shown in the RR graphs above of decades ago is not
visible in these data.

The article, "On the Efficiency of Bicycle Chain Drives" is
particularly interesting as well.


I don't see anything interesting in that piece because the
measurements are not normalized to be comparable. Behind all this
testing is the simple concept that chain efficiency depends on
articulation angle for one cycle under load, nothing less. What
conclusions are we to draw from these measurements and to what good can
they be used?

I see this a s a major snow-job that obscures the essence to what the
test titles allude.

Jobst Brandt
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  #52  
Old July 29th 05, 02:32 AM
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Default Nobody knows about RR

On Thu, 28 Jul 2005 23:17:25 GMT,
wrote:

Neil Brooks writes:

I thought that makers of bicycle tires would have experimentally or
scientifically based knowledge as a foundation of their
production.


I jumped in late and, unfortunately, haven't caught this thread in
its entirety, so forgive me if this has already been posted.


Interesting article:


Adobe document p.8
Magazine p.14


http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf

Along with its testing and conclusions, it makes reference to the
following sources (which I haven't attempted to locate) of RR test
data:


Cycling Plus, issue 62 (Feb. ?97) ?Winter tyres?; Cycling Plus, issue
68 (Mid-summer ?97) ?Road tyres?; Cycling Plus, issue 81 (Aug ?98)
?Time-trial tyres?; Total Bike, issue 6 (Oct ?97) ?MTB tyres?; and
BHPC Newsletter, issue 58, ?MTB tyres?.


The section on rolling resistance (pp 14) has a disconcerting flavor
to it in two ways. First the author attempts to establish credibility
through his years as an engineer and long association with recumbents.
Then the test method is explained showing that no direct measurements
of drag were used but rather the derivation of drag by differentiation
of rolling speed.

http://www.terrymorse.com/bike/imgs/rolres.gif

Printing a table of myriad numbers may be a good archive but such data
is better displayed in curves and preferably curves made of more than
one data point. What we have in the IHPVA report is none of that. In
fact the information shown in the RR graphs above of decades ago is not
visible in these data.

The article, "On the Efficiency of Bicycle Chain Drives" is
particularly interesting as well.


I don't see anything interesting in that piece because the
measurements are not normalized to be comparable. Behind all this
testing is the simple concept that chain efficiency depends on
articulation angle for one cycle under load, nothing less. What
conclusions are we to draw from these measurements and to what good can
they be used?

I see this a s a major snow-job that obscures the essence to what the
test titles allude.

Jobst Brandt


Dear Jobst,

Gosh, I never expected you to disparage anyone writing about
the technical side of bicycling!

Do you know of anyone whose work is vastly superior in every
respect to everyone else and is aslo much more interesting?

Hopefully,

Carl Fogel
  #53  
Old July 29th 05, 04:54 PM
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Default Nobody knows about RR


Jasper Janssen wrote:
On 28 Jul 2005 10:00:30 -0700, wrote:
Jasper Janssen wrote:
On Tue, 14 Jun 2005 20:37:01 -0500, jbuch
wrote:

Because of the greater dollar and sales volume and greater consumption,
there may be a better technology basis in Automotive Tires. At least,
in the late 1960's tire companies were out hiring brand new PhD
graduates from my engineering school.

On the other hand, the confirming data and experiments may be company
proprietary, and unpublished.

Formula 1 tires, in particular, are extremely well-researched. But the
results are also so secret that the actual F1 teams aren't even allowed to
touch the tires that the tyre manufacturers provide them with.


Must be hard to put them on the car without touching them. I could have
sworn that I've seen pit crews change tires in F1 races.


You didn't see pit crews change them, you saw tire manufacturer people
change them, only nominally part of the team's piut crew. Tires come in
their own trucks and have their own people.


So you're saying that Ferrari's pit crew that does the super fast tire
changes are actually Bridgestone techies cleverly disguised in Ferrari
uniforms? I have to admit that with the full coverage helmets they wear
these days, they could be anyone.

If you get the impression I don't believe that the teams aren't allowed
to touch the tires, you're right. I do believe that it's quite likely
that tire company techs do the actual mounting of the tires onto the
wheels.

 




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